Electric switch and venting system therefor



Dec. 3, 1929. c. D. AINSWORTH ELECTRIC SWITCH AND VENTING SYSTEM THEREFOR Filed March 30, 1927 2 Sheets-Sheet 1 17110877702. M.WL

Dec. 3, 1929.

C. D. AINSWORTH ELECTRIC SWITCH AND VENTING SYSTEM THEREFOR Filed March 30, 1927 2 Sheets-Sheet 2 4 a ,4. i ZIII Ill" Patented Dec. 3, 1929 UNITED STATES PATENT OFFICE CHESTER D. AINSWORTH, F WOLLASTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELECTRICAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS,

A CORPORATION 015 MASSACHUSETTS ELECTRIC SWITCH AND VENTING SYSTEM THEREFOR Application filed'March 30, 1927.

from the casing.

A further object is generally to improve upon electric switches and venting systems therefor.

Fig. 1 is aplan view of a three-phase switching unit embodying the invention.

Fig. 2'isa side view of one of the switches ofthe unit.

Fig. 3 is a diagrammatic representation of a venting system.

oil and gas separator.

Figs. 5 and 6 are plan views respectively illustrating the two types of baflle plates contained in the gas separator shown in Fig. 4.

Fig. 7 is a sectional view of the check valve having provision for the free return of oil from the conservator tank to the switch casing after circuit interruption.

Fig. 8 1s a sectional view taken along l ne 88 of Fig.7.

The invention is here shown applied to the three-phase switch unithaving the three independent oil containing casings 10 provided with insulated terminals 12 which extend into the oil in the casing and have stationary contact members, not shown, within the oil which cooperate with movable contact memherein the usual manner to control the circuit through the switch.

When the switch is opened under heavy load large volumes of oil gas and vapor may be generated by the circuit interrupting arc and a large amount of liquid oil may be thrown upwardly and out of the vent pasventing system embodying this invention is adapt'ed to permit the escape of gases and vapors and to catch the expelled oil and subsequently return it to the switch casing and includes a-gasseparator 14 and a storage or Fig. 4 is asectional elevation through the sage usually provided in such a switch. The- Serial No. 179,500.

conservator tank 16 in which the expelled oil is adapted temporarily to be stored.

A vent pipe 18 is in communication with the top of the switch casing and serves to conduct the mixture of oil and oil gases and vapors into the inlet 20 of the separator. The conservator tank has a pipe 22 extending from the bottom thereof and in communication with the oil outlet passage of the separator. The separator is provided with a nozzle 26 formed by cooperation of the inclined plate 28 with the bottom wall of the separator casing through which nozzle the mixture of liquid oil and gases and vapors are adapted to be discharged. An entrance 30 is provided above the nozzle 26 which communicates with the bottom of a separator compartment 32. Liquid oil and vapors are discharged with considerable force from-the switch casing and the liquid oil is directed by the nozzle 26 in to the pipe 22 and thence into the conservator tank 16. The gases separate from the oil at the outlet of the nozzle and pass-through the entrance 3O upwardly into the separator compartment 32. The separator compartment is occupied by a stack of superposed and alts. nately disposed discs 34 and 36 respectively separated by spacing rings 37. The discs 36 are characterized by having perforations near the center thereof while the discs 34 are characterized'by having perforations near the periphery thereof so that a tortuous path is provided through the stack of discs, whereby the gases are cooled and small particles of oil are separated'out of the gas. The gas passes from the upper portion of the separator compartment through an outlet passage 38 and into a discharge pipe 40. The stack of discs is held in place upon the ledge 42 by the removable cover 44 which is screw threaded ontothe top of the separator compartment.

The conservator tank 16 is elevated above the top of the switch casing and the pipes 22 and 18 are inclined downwardly from the tank to the casing so that the oil entrapped in the conservator tank can return immediately into the switch casing as soon as pressure conditions within the switch casingpermi The conservator tank is air tight so the. compressed air cushion entrapped in the tam:

above the oil therein expands and rapidly returns the oil to the switch casing. The dimensions of the nozzle 26 and the inlet 30 to the separator compartment are such that the oil on its return to the switch casing flows through the nozzle and does not rise to any considerable extent in the separator compartment.

Under some conditions, it is desirable to restrict the outflow of liquid oil and gases from the switch casing. It is also desirable to return the expelled oil to the switch casing as rapidly as possible after circuit interruption so that the switch can repeatedly close and open rapidly under full head of oil. To this end a check valve 46 is interposed in the pipe 18 between the gas separator and the switch casing. The check valve has a wall 48 therein provided with an aperture 50 which aperture is normally covered by a hinged plate 52 which is provided with a small opening 54 therein. The valve is so arranged in the pipe that the outflowing gas and oil from the switch hold the plate 52 upon its seat so that the size of the small opening 54 governs the rate at which the gas and oil can be expelled from the switch. The plate 52 is adapted to swing away to uncover the opening 50 however, under action of the returning oil from the conservator tank, thereby to permit the oil to pass rapidly into the switch casing.

The idea of a gas and liquid separator with means to guide relatively large bodies of liquid oil past the separator inlet and collect the oil and subsequently return it to the switch casing is disclosed in a co-pending application of William S. Edsall Serial No. 595,173, filed October 17, 1922, and assigned to the assignee of this application.

The term oil herein employed is intended to embrace generally any suitable arc-quenching liquid.

I claim:

1. The combination of a liquid containing casing and a venting system therefor including a vent pipe having an elevated conservator tank at the end thereof and a gas outlet passage between the tank and the easing, said pipe being freely open between said tank and the casing to admit the return flow of expelled liquid from the tank to the casing.

2. The combination of a liquid containing casing and a venting system therefor including a vent pipe having an elevated conservator tank at the end thereof and a gas outlet passage between the tank and the easing, and means interposed in said pipe between said outlet passage and casing to restrict the outward flow of liquid and gas in said pipe having provision for the unrestricted return flow of liquid from said tank to the casing.

3. The combination of a liquid containing casing and a venting system therefor comprising a pipe in communication at one end with the interior of the casing, a gas tight conservator tank in communication with the other end of said pipe, a gas separator having a gas inlet in communication with an intermediate section of said pipe, and means to direct liquid masses past said inlet into said conservator tank.

4. The combination of a liquid containing casing and a venting system therefor comprising a pipe in communication with the interior of the casing, an elevated conservator tank in communication with the free end of said pipe, a gas separator having a gas inlet in communication with an intermediate section of said pipe, and means to direct liquid masses past said inlet into said conservator tank, said means comprising a nozzle disposed beneath said gas inlet and in communication both with said inlet and with said ipe between said inlet and conservator tan 5. The combination of a liquid containing casing and a venting system therefor comprising a pipe in communication with the interior of the casing, an elevated conservator tank in communication with the free end of said pipe, a gas separator having a gas inlet in communication with an intermediate section of said pipe, and means to direct liquid masses past said inlet into said conservator tank, said pipe being freely open for the return flow of liquid from said conservator tank to the casing.

6. The combination of a liquid containing casing and a venting system therefor comprising a vent pipe in communication with the interior of the casing at one end, an elevated conservator tank in communication at its lower end with the other end of said pipe, a gas separator having a gas inlet in communication with an intermediate section of said pipe, and means to direct liquid masses to flow by their momentum past said inlet and into said conservator tank.

7. The combination of an oil containing casing, a vent pipe in communication with said casing above the oil level therein, an elevated gas tight conservator tank in communication at the bottom thereof with the free end of said vent pipe and characterized by temporarily retaining oil therein and an entrapped compressed gas cushion above the oil, and a gas separator in communication with said pipe between the casing and said tank.

8. The method of vent-ing an enclosed liquid containing casing and returning the vented liquid to the casing which consists in passing the vented liquid from the casing, entrapping the liquid in a closed tank under a gas cushion compressed by the inflow of liquid into said tank, separating gas from the-liquid during its passage from said casing to said tank, and utilizing the pressure of said entrapped gas cushion to return the entrapped liquid subsequently to the casing.

9. The method of venting an enclosed liquid containing casing and returning liquid to the casing which consists in passing the vented liquid from the casing into an elevated tank, separating gas from the liquid during its passage from said casing to said tank, and subsequently returning the entrapped liquid to the casing.

10. An enclosing casing adapted to contain a liquid, a vent pipe in communication with said casing above the normal liquid level therein, automatically operative, pressure-applying means in communication with said vent pipe to return to said casing through said vent pipe, and means to separate gas from the liquid in said vent pipe under a force greater than gravity the liquid eX- pelled therefrom.

11. The combination of a liquid containing casing, a conservator receptacle, and a conduit extended therebetween having gas separating means communicating with an intermediate portion of the conduit.

In testimony whereof, I have signed my name to this specification.

CHESTER D. AINSWORTH. 

